This invention relates to a special image effect producing apparatus with a memory selection, and more particularly, to an apparatus for selectively producing special effect waveforms, for example called "wipe", for switching a TV picture with special image effects.
As is well known, in producing television programs, it is frequently performed to switch the TV picture with special effects. A "wipe" is the technique of wiping out a part of the present picture on the TV screen and inserting another picture into the wiped-out portion. Many waveforms are generated and one of them is selected for wipe waveform generation.
The conventional technique for selectively generating the wipe waveform is generally classified into two types. One of them is to use a rotary switch, as shown in FIGS. 1A and 1B. The other is to use a cartridge, as shown in FIGS. 2A and 2B.
The rotary switch technique will be described first.
The front view of a waveform pattern select switch 12, which is provided on the front panel of the related apparatus, is shown in FIG. 1A. A plurality of waveform patterns 11, which correspond to various types of wipe waveforms, are arranged around pattern select switch 12. During operation, an operator sets the pointer of pattern select switch 12 to a desired wipe waveform of those patterns 11.
FIG. 1B shows an electrical scheme of waveform pattern select switch 12 containing its signal processing system. In the figure, select switch 12 contains fixed terminals 12a to 12n. Waveform patterns 11 are provided in association with those fixed terminals. Movable terminal 12o of select switch 12 is moved to be in contact with one of the fixed terminals 12a to 12n, for a desired waveform selection. Fixed terminals 12a to 12n are connected to waveform code converter 13.
The output signal from code converter 13 is transferred in the form of waveform code 13a to wipe waveform generator 14. Responsive to the output signal, generator 14 generates a corresponding wipe waveform. For a desired wipe waveform, the operator turns movable terminal 12o to connect it to the fixed terminal associated with a desired waveform indication. The signal from the selected fixed terminal drives waveform code converter 13. Converter 13 produces a waveform code representative of the desired waveform pattern, and applies it to wipe waveform generator 14.
The cartridge technique for wipe waveform generation will be described referring to FIGS. 2A and 2B. As shown, cartridge 26 is provided with waveform pattern 21 on the top, and holes 22 on one of the sides of the cartridge. The holes 22 are arrayed so as to represent a waveform code of waveform pattern 21.
Light-emitting diodes (LEDs) 23 are paired with photo diodes 24. Each of these pairs is installed on both sides of each hole 22, as shown. Photo diodes 24 are contained in waveform code converter 27. The number of cartridges 26 used is equal to that of the possible wipe waveforms.
In use, cartridge 26 with a desired wipe waveform is coupled with waveform code converter 27. LEDs 23 are energized to emit light. Phototransistor 24 receives the light and is turned on. Transistors 24, located corresponding to non-hole portions of cartridge 26, are left turned off. An on/off pattern of those phototransistors 24 is transferred in the form of waveform code 27a to wipe waveform generator 25. Then generator 25 generates a wipe waveform, which corresponds to waveform code 27a.
The rotary switch technique of FIGS. 1A and 1B has a disadvantage in that the number of selectable waveforms is limited to the number of fixed terminals of rotary switch 12.
The cartridge technique of FIGS. 2A and 2B is advantageous in that the waveform pattern marked on the top of the cartridge is easy for the operator to see. This technique, however, requires many cartridges, that is, the number of cartridges is equal to that of the necessary waveforms. This fact leads to various inconvenient problems. For example, ample space is needed for cartridge storage, and loss of cartridges may often occur.